wrong player accepting free throws

[Hawks Coach]

Rule 10 Fouls and Penalties
SECTION 3 PLAYER TECHNICAL
A player shall not:
ART. 8 . . . Commit an unsporting foul. This includes, but is not limited to, acts or conduct such as:
f. Knowingly attempting a free throw or accepting a foul to which the player was not entitled.

You can call the T if you believe that there was an intent to deceive. If it is an honest mistake (e.g., you call an off-ball foul and player with ball goes to shoot the FT), no T. In this case, it doesn't sound like there was cause for confusion, but you may want to confer before assessing a T just to be sure. You should never T the misunderstanding, just the willful unsporting act. with the T, you now empty the lane and let A1 shoot, then B selects a shooter for the T, then B inbounds opposite the table.

In addition and BTW, if A2 had shot one or both FTs before you noticed, regardless of the result OR the intent, this is a correctable error (timeliness of noticing the error is also relevant- see correctable errors). You would have A1 shoot the FTs, then go to the shots for the T if you felt that A2 had intentionally tried to shoot for A1.